A webserver often stores a set of data objects, such as HTML pages, media objects, data stores, and executable scripts, that are provided to a web browser and rendered thereby to present a set of web pages comprising a website. Web browsers typically include a browser cache where received items may be stored for reuse in subsequently rendered web pages, thereby improving the performance of the web browser, economizing the resources of the webserver, and optionally providing limited capabilities to render the web pages when the webserver cannot be accessed. In contrast with other types of data objects within a computer system (such as user documents, application and operating system binaries, and application configuration information), the data objects contained in the browser cache have typically been regarded as temporary and disposable.